Electric discharge tube



ELECTRIC DISCHARGE TUBE Filed July 2, 1926 Patented Mar. 26, 1929.

UNITED STATES PATENT OFFICE.

.REINHOLD Rlj'DENBERG, F BERLIN-GRUNEWALD, GERMANY, ASSIGNOR TO. SIEMENS- SCHUCKERTWEBKE GESELLSGHAFT MIT BESCHRANKTEIR, HAITUNG, OF SIEMENS- STADT, NEAR BERLIN, GERMANY, A CORPORATION OF GERMANY.

ELECTRIC DISCHARGE TUBE.

Application filed July 2, 1926, Serial No.

My invention relates to electric discharge tubes with gaseous cathodes.

In electric discharge tubes, more particularly in electron tubes operating with a.

qualitative relay effect, a gaseous or vaporous cathode may be employed by forming a discharge are of mercury vapor, for in stance by means of two auxiliary electrodes, and using said are as cathode of the tube. By the action of the potential difference between said are and the anode of the tube the electrons are emitted from the arc space and reach the anode. Preferably the space containing the anode of the tube, or the it control electrodes respectively, is kept at lower pressure than the pressure within or about the vaporous cathode, since it is Well known that the anode current may only be accurately controlled by the grid if the an evacuation in the control space has reached a certain value.

The object of my invention is to construct an electron tube of the above mentioned kind, by means of which it is possible to to maintain a sufficiently high vacuum in the space of the anode or of the control electrodes in spite of the fact that in addition to the electrons gaseous molecules also constantly escape from the cathode space proper into the anode space.

According to my invention frictional resistances are interposed between the space of the cathode and that of the anode or control-electrodes respectively which resist anccs are cooled and are traversed by the gas of the cathode passing into the anode space owing to a condensation or to a suction efi'ect. A high-vacuum pump may for example be put in communication with the anode space by means of which the gas is drawn through the frictional resistances from the cathode space into the anode space. The frictional resistances increase the difference of pressure between the cathode space and anode space in such a manner, that a sufiiciently high vacuum will prevail in the space of the anode or of the control electrodes respectively. The electrons emitted from the discharge are pass through the openings of the frictional resistances to the anode. As frictional resistance a naturally porous diaphragm, or a diaphragm artifi-.

cially provided with suitable openings may be employed. An embodiment of my in- 120,191, and in Germany June 26, 1925.

vention is diagrammatically represented, by way of example, in the accompanying drawings, in which Figure 1 represents a longitudinal vertical section through a discharge tube, and

Figure 2 represents a transverse section on the line A--B Figure 1.

The electric discharge tube operating with a quantative relay effect contains a cathode space 1, a space 2 for the anode 3 and a control grid 4. In the cathode space are situated two auxiliary electrodes 5-and 6 for producing a mercury vapor are acting as cathode. The auxiliary electrodes are supphed with direct current from a source 7. Between the anode space and the cathode space are inserted frictional resistance elements 8, which form between each cury vapor may amount to about 10' mm.,

while in the anode space a pressure of 10" mm. mercury column prevails.

Instead of sucking off the gases from the anode space by means of a pump, the gases may also be condensed by cooling the anode space by a cooling jacket 10, which also surrounds the frictional resistance elements 8, thereby cooling them. The result of this expedient is that the major portion of the vapor or other gaseous matter in passing through theresistance body is condensed at the elements 8 and thereby prevented from passing into the control electrode and anode space.

Various modifications and chan es may be made without departing from t e spirit and scope of the invention, and I desire therefore that only such limitations shall be placed thereon as are imposed by the prior art.

What I claim as new and desire to secure by Letters Patent is The combination with an electric disspace of the control electrode, and means charge tube having a gaseous cathode, an for cooling said frictional resistances, so anode and a control electrode between said that the gaseous particles, passing said re- 10 cathodeand anode, of frictional resistances sistances, are deposited on the latter.

I inserted between the cathode and the con- In testimony whereofI afiix my signature.

trol electrode and adapted to be traversed:

by the gases of the cathode passing into the REINHOLD RUDENBERG. 

